Helium microwave-induced plasma mass

Story WC, Caruso JA. 1993. Gas chromatographic determination of phosphorus, sulfur and halogens using a water-cooled torch with reduced-pressure helium microwave-induced plasma mass spectrometry. J Anal Atomic Spectrometry 8 571-575. 

Suyani, H., Creed, J., Caruso, J. and Satzger, R.D. (1989) Helium microwave-induced plasma mass spectrometry for capillary gas chromatographic detection speciation of organotin compounds./. Anal. At. Spectrom., 4, 777-782. 

Creed J. T., Davidson T. M., Shen W. and Caruso J. A. (1990) Low-pressure helium microwave-induced plasma mass spectrometry for the detection of halogenated gas chromatographic effluents, J Anal At Spectrom 5 109—113. 

Fecher P.A. A. Nagengast. (1994). Trace analysis in high matrix aqueous-solutions using helium microwave-induced plasma-mass spectrometry. /. Anal. At. Spectrom., Vol.9, ppl021-1027, ISSN 1364-5544... 

Work performed by the Caruso group [3,106-109] has encompassed several studies of the use of a He-MIP with mass spectrometric detection for chromatography, with particular application to speciation studies. As mentioned previously, the helium microwave induced plasma offers several advantages over conventional ICP-... 

Figure 19 Helium microwave induced plasma (M1P) torch used in MIP mass spectrometry (MIP-MS) sampling for capillary gas chromatography (GC) detection. (From Ref. 110.)...

Olson, L.K. Caruso, J.A. The helium microwave-induced plasma—An alternative ion-source for plasma-mass spectrometry. Spectrochim. Acta, Part B 1994, 49, 7-30. 

The gas chromatograph may be interfaced with atomic spectroscopic instruments for specific element detection. This powerful combination is useful for speci-ation of different forms of toxic elements in the environment. For example, a helium microwave induced plasma atomic emission detector (AED) has been used to detect volatile methyl and ethyl derivatives of mercury in fish, separated by GC. Also, gas chromatographs are interfaced to inductively coupled plasma-mass spectrometers (ICP-MS) in which atomic isotopic species from the plasma are introduced into a mass spectrometer (see Section 20.10 for a description of mass spectrometry), for very sensitive simultaneous detection of species of several elements. 

Satzger RD, Fricke FL, Brown PG, Caruso JA (1987) Detection of halogens as positive ions using a helium microwave induced plasma as an ion source for mass spectrometry. Spectrochim Acta 42B 705-712. 

As SFC provides gaseous sample introduction to the plasma and thus near-100 % analyte transport efficiency, coupling SFC with plasma mass spectrometry offers the potential of a highly sensitive, element-selective chromatographic detector for many elements. Helium high-efficiency microwave-induced plasma has been proposed as an element-selective detector for both pSFC and cSFC [467,468] easy hyphenation of pSFC to AED has been reported [213]. 

Other frequently used methods for determining fluoride include ion and gas chromatography [150,204,205] and aluminium monofluoride (AIF) molecular absorption spectrometry [206,207]. Less frequently employed methods include enzymatic [208], catalytic [209], polarographic [210] and voltammetric methods [211], helium microwave-induced [212] or inductively coupled plasma atomic emission spectrometry [213], electrothermal atomic absorption spectrometry [214], inductively coupled plasma-mass spectrometry [215], radioactivation [216], proton-induced gamma emission [217], near-infrared spectroscopy [218] and neutron activation analysis [219]. 

The argon ICP is by far the most common type of plasma to be coupled with mass spectrometric detection. As discussed above, alternative gas and mixed gas plasmas have been used, but several other types of plasma have also been employed one such plasma is the microwave-induced plasma (MIP). The MIP usually utilises helium and is therefore very highly ionising. It suffers far fewer interference problems than argon-based plasmas, although traditionally it has had the reputation of not being a very robust plasma, i.e. it is easily extinguished by the... 

Common gas chromatographic detectors that are not element- or metal-specific, atomic absorption and atomic emission detectors that are element-specific, and mass spectrometric detectors have all been used with the hydride systems. Flame atomic absorption and emission spectrometers do not have sufficiently low detection limits to be useful for trace element work. Atomic fluorescence [37] and molecular flame emission [38-40] were used by a few investigators only. The most frequently employed detectors are based on microwave-induced plasma emission, helium glow discharges, and quartz tube atomizers with atomic absorption spectrometers. A review of such systems as applied to the determination of arsenic, associated with an extensive bibliography, is available in the literature [36]. In addition, a continuous hydride generation system was coupled to a direct-current plasma emission spectrometer for the determination of arsenite, arsenate, and total arsenic in water and tuna fish samples [41]. 

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